Glowing Tombstone
Sauk Centre, Minnesota
The tombstone is large and it only has the name BOSS on it. According to Chad Lewis and Terry Fisk in their Haunted Locations Minnesota guide, the tombstone glows at night -- although they concede it could be just light reflected from the nearby town.
Other reports describe this as a "flashing" tombstone, and dismiss it as moonlight bouncing off of a rotating restaurant sign. That sounds like a stretch -- what business bothers to rotate an unlit, moonlight-reflecting sign at night?